imo with larger subs they do sound better on the water... the water seems to tighten everything up.. my last boat with one single 15 sounded like crap in the driveway but when it was in the water sounded great..

Richard's boat with two 15s is probably the exception to the rule for your question. Most of us other humble people with a 12 or two will typically hear better performance in a quiet surrounding. Keep in mind Richard's system is rivals some small stadiums... LOL.